Copper oxide rectifier



Patented Aug. 25, 1931 UNITED, STATES PATENT OFFICE CHARLES K. STROIBEL, OF PITTSBURGH, PENNSYLVANIA, ASSICtNO It TO THE UNION SWITCH & SIGNAL COMPANY, OF SWI OI IPENNSYLVANLA No Drawing.

My invention relates to copper oxide rectifiers, and has for an object the provision of a novel and improved method of manufacturing a high. resistance'rectifier of thisv type.

I will describe one method embodying'my invention, and will then point out the novel features thereof in claims.

- I In accordance with my invention, a copper blank is first cleaned, and is then placed in an oxidizing furnace maintained at a relatively high temperature, such for example, as 1860 Fahrenheit. It is then removed from such furnace and placed in a second furnace maintained at a lower temperature, such for exam 1e, as 1040 F ahrenheit. The oxidized Blank is then removed from the second furnace and allowed to cool in still air at room temperature. The

blank may be left in the first furnace for. approximately 15 minutes, and in the second furnace for approximately 4 minutes.

Heretoforeuthe standard method of producing copper oxide rectifiers has involved heating the copper blank in a first furnace maintained at a relatively high temperature, transferring the oxidized blank to a second a lower. temperature,

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resistance in the'high resistance direction increases with voltage from an initial value at zero volts to a, maximum value at about 2 volts, and then-decreases with increase of voltage. I have found that when the copper blank is treated in only the first furnace and is then allowed to rectifier has a different voltage-resistance characteristic; in this case, the high resistance increases with. voltage up to about 15 volts, and then decreases slowly with increase of voltage. By. manufacturing rectifiers in accordance with my present invention, the resistance in the hlgh resistance direction increases with volta e up to about 15 volts, and then decreases s owly with increased voltageiin such a manner that the resistance at 30 volts is about the same as the resistance at 2 volts, this resistance value being about 10,000

ohms. The resistance in Application filed June 18,

cool slowly in air, the

COPPER OXIDE RECTIFIER 1930. Serial No. 462,145.

the low resistance direction is lower than that of anunquenched rectifier made by the one furnace treatment. Furthermore, an unquenched rectifier made by the two-furnace treatment has an advantage over a rectifier made by the sin le-furnace treatment, in that the aging un er load is less severe in the former casethan in the latter,

Rectifiers embodying my invention are particularly well adapted for use where high resistance is desirable, such for example, as B battery eliminators employed in connection with radio receiving apparatus.

Althoughl have herein described only one method of rectifier manufacture em- 'bodying my invention, it is understood that oxide rectifier which consists in placinga copper blank in an oxldizing furnace mam tained at substantially l860 Fahrenheit for 15 minutes, removing the blank from such furnaceeand placing it ina second furnace maintained at substantially 1040 Fahrenheit-Ifor approximately 4 minutes and then removing the oxidized blank and allowing it'to cool slowly in still air to room tem- I perature.

oxide rectifier which consists in heating a copper blank in a furnace maintained at a re atively high temperature, 'placing the oxidized blank in a second furnace maintained at a-lower temperature and then allowing the oxidized blank to cool slowly in still air to room-temperature.

Intestimony whereof I aflix my signature.

CHARLES K STROBEL;

scope of the ap- 2, The method of manufacturing a copper 

